/*-------------------------------------------------------------------------
 *
 * getrusage.c
 *      get information about resource utilisation
 *
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *      src/port/getrusage.c
 *
 *-------------------------------------------------------------------------
 */

#include "c.h"

#include "rusagestub.h"

/* This code works on:
 *        solaris_i386
 *        solaris_sparc
 *        hpux 9.*
 *        win32
 * which currently is all the supported platforms that don't have a
 * native version of getrusage().  So, if configure decides to compile
 * this file at all, we just use this version unconditionally.
 */

int
getrusage(int who, struct rusage *rusage)
{// #lizard forgives
#ifdef WIN32
    FILETIME    starttime;
    FILETIME    exittime;
    FILETIME    kerneltime;
    FILETIME    usertime;
    ULARGE_INTEGER li;

    if (who != RUSAGE_SELF)
    {
        /* Only RUSAGE_SELF is supported in this implementation for now */
        errno = EINVAL;
        return -1;
    }

    if (rusage == (struct rusage *) NULL)
    {
        errno = EFAULT;
        return -1;
    }
    memset(rusage, 0, sizeof(struct rusage));
    if (GetProcessTimes(GetCurrentProcess(),
                        &starttime, &exittime, &kerneltime, &usertime) == 0)
    {
        _dosmaperr(GetLastError());
        return -1;
    }

    /* Convert FILETIMEs (0.1 us) to struct timeval */
    memcpy(&li, &kerneltime, sizeof(FILETIME));
    li.QuadPart /= 10L;            /* Convert to microseconds */
    rusage->ru_stime.tv_sec = li.QuadPart / 1000000L;
    rusage->ru_stime.tv_usec = li.QuadPart % 1000000L;

    memcpy(&li, &usertime, sizeof(FILETIME));
    li.QuadPart /= 10L;            /* Convert to microseconds */
    rusage->ru_utime.tv_sec = li.QuadPart / 1000000L;
    rusage->ru_utime.tv_usec = li.QuadPart % 1000000L;
#else                            /* all but WIN32 */

    struct tms    tms;
    int            tick_rate = CLK_TCK;    /* ticks per second */
    clock_t        u,
                s;

    if (rusage == (struct rusage *) NULL)
    {
        errno = EFAULT;
        return -1;
    }
    if (times(&tms) < 0)
    {
        /* errno set by times */
        return -1;
    }
    switch (who)
    {
        case RUSAGE_SELF:
            u = tms.tms_utime;
            s = tms.tms_stime;
            break;
        case RUSAGE_CHILDREN:
            u = tms.tms_cutime;
            s = tms.tms_cstime;
            break;
        default:
            errno = EINVAL;
            return -1;
    }
#define TICK_TO_SEC(T, RATE)    ((T)/(RATE))
#define TICK_TO_USEC(T,RATE)    (((T)%(RATE)*1000000)/RATE)
    rusage->ru_utime.tv_sec = TICK_TO_SEC(u, tick_rate);
    rusage->ru_utime.tv_usec = TICK_TO_USEC(u, tick_rate);
    rusage->ru_stime.tv_sec = TICK_TO_SEC(s, tick_rate);
    rusage->ru_stime.tv_usec = TICK_TO_USEC(u, tick_rate);
#endif                            /* WIN32 */

    return 0;
}
